Demon Slayer - The Movie: Mugen Train made a very large sum of money at the box office, so of course the series is being capped off with three more films.
The release of Demon Slayer - The Movie: Mugen train was probably a bit of lightning in a bottle. It came out in October of 2020 in Japan, when there wasn't a huge amount of competition due to COVID, and people were able to go out and about (even if maybe they shouldn't have). This led to the film becoming the highest grossing film in Japan ever, taking home more than 40 billion yen, almost an entire 10 billion yen more than the previous record holder Spirited Away (which was released in 2021, mind you). So, it's wholly unsurprising that, following the final episode of the current season of anime, the official Japanese Demon Slayer Twitter account shared that the manga's final arc will be covered by a trilogy of movies.
This announcement will likely be welcomed by many fans of the series, as Mugen Train was a big event over in the West too, and it was paired with a teaser trailer that you can check out above. It doesn't show all that much, but it's obviously hinting at the series' last arc, Infinity Castle. Crunchyroll and Sony also announced that they had acquired the trio of movies for a global theatrical release (except for certain Asian territories and Japan). A release date hasn't been set just yet, and it's unclear how soon the films will release after one another, but we can probably expect something like a late 2025 release, or very early 2026 at the latest.
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